The use of chemical compounds to control fungal diseases of plants is well known.
In contrast, the use of chemical compounds to control viral diseases is not presently done on any large commercial scale. However, certain compounds have been reported as having an antiviral activity, such as certain 2-substituted benzimidazoles against tobacco mosaic virus (TMV), Cassells et al., Z. Naturforsch. C. Biosic, 1982, 37c (5-6) 390-3; poly-(2-methyl-5-virylpyridine N-oxide against TMV, Sugimura et al., J. Agric. Food Chem., 1983 31(3), 665-7; certain thiadiazoles against potato X virus, Schuster et al., East German Pat. No. 157,664, 1982; and certain 3-trihalomethyl-5-ureido-1,2,4-oxadiazoles and -1,2,4-thiadiazoles against southern bean mosaic virus, Gay et al., U.S. Pat. No. 4,353,920, 1982.
Virus diseases of food crops or other plant crops include: tobacco mosaic, cucumber mosaic, bean common mosaic, bean yellow mosaic, and necrotic ring spot of stone fruits (prunus necrotic ring spot virus).